/Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/Framework/UncheckedArray.h
This is for use in critical path code where bounds checking would be costly and we want to ship a build with most asserts enabled (e.g. the server)
template<int32 NumInlineElements> class TUncheckedFixedAllocator : public [TFixedAllocator< NumInlineElements >](API\Runtime\Core\Containers\TFixedAllocator)